﻿using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Runtime.Serialization.Json;
using System.IO;
using System.Text.RegularExpressions;  

namespace ECCIT.Extension.Weibo_v2.Common
{
    /// <summary>
    /// Provides methods for JSON serialization.
    /// </summary>
    public static class JsonSerializationHelper
    {
        /// <summary>
        /// Deserializers a JSON string into an strong-typed object.
        /// </summary>
        /// <typeparam name="T"></typeparam>
        /// <param name="jsonStr"></param>
        /// <returns></returns>
        public static T JsonToObject<T>(string jsonStr) where T : class
        {
            T result = null;
            DataContractJsonSerializer ser = new DataContractJsonSerializer(typeof(T));

            using (var ms = new MemoryStream(Encoding.UTF8.GetBytes(jsonStr)))
            {
                result = ser.ReadObject(ms) as T;
            }

            return result;
        }

        public static void ObjectToJson(object target, string targetFileLocation)
        {
            DataContractJsonSerializer ser = new DataContractJsonSerializer(target.GetType());

            using (var fs = File.OpenWrite(targetFileLocation))
            {
                ser.WriteObject(fs, target);
            }
        }

        public static string ObjectToJson(object target)
        {
            DataContractJsonSerializer ser = new DataContractJsonSerializer(target.GetType());
            string result = string.Empty;

            using (var ms = new MemoryStream())
            {
                ser.WriteObject(ms, target);

                ms.Position = 0;
                StreamReader sReader = new StreamReader(ms);
                result = sReader.ReadToEnd();
            }

            return result;
        }

        /// <summary>    
        /// JSON序列化    
        /// </summary>    
        public static string JsonSerializer<T>(T t)
        {
            DataContractJsonSerializer ser = new DataContractJsonSerializer(typeof(T));
            MemoryStream ms = new MemoryStream();
            ser.WriteObject(ms, t);
            string jsonString = Encoding.UTF8.GetString(ms.ToArray());
            ms.Close();
            //替换Json的Date字符串    
            string p = @"///Date/((/d+)/+/d+/)///"; /*////Date/((([/+/-]/d+)|(/d+))[/+/-]/d+/)////*/
            MatchEvaluator matchEvaluator = new MatchEvaluator(ConvertJsonDateToDateString);
            Regex reg = new Regex(p);
            jsonString = reg.Replace(jsonString, matchEvaluator);
            return jsonString;
        }
        /// <summary>    
        /// JSON反序列化    
        /// </summary>    
        public static T JsonDeserialize<T>(string jsonString)
        {
            //将"yyyy-MM-dd HH:mm:ss"格式的字符串转为"//Date(1294499956278+0800)//"格式    
            string p = @"/d{4}-/d{2}-/d{2}/s/d{2}:/d{2}:/d{2}";
            MatchEvaluator matchEvaluator = new MatchEvaluator(ConvertDateStringToJsonDate);
            Regex reg = new Regex(p);
            jsonString = reg.Replace(jsonString, matchEvaluator);
            DataContractJsonSerializer ser = new DataContractJsonSerializer(typeof(T));
            MemoryStream ms = new MemoryStream(Encoding.UTF8.GetBytes(jsonString));
            T obj = (T)ser.ReadObject(ms);
            return obj;
        }

        /// <summary>    
        /// 将Json序列化的时间由/Date(1294499956278+0800)转为字符串    
        /// </summary>    
        private static string ConvertJsonDateToDateString(Match m)
        {
            string result = string.Empty;
            DateTime dt = new DateTime(1970, 1, 1);
            dt = dt.AddMilliseconds(long.Parse(m.Groups[1].Value));
            dt = dt.ToLocalTime();
            result = dt.ToString("yyyy-MM-dd HH:mm:ss");
            return result;
        }
        /// <summary>    
        /// 将时间字符串转为Json时间    
        /// </summary>    
        private static string ConvertDateStringToJsonDate(Match m)
        {
            string result = string.Empty;
            DateTime dt = DateTime.Parse(m.Groups[0].Value);
            dt = dt.ToUniversalTime();
            TimeSpan ts = dt - DateTime.Parse("1970-01-01");
            result = string.Format("///Date({0}+0800)///", ts.TotalMilliseconds);
            return result;
        }
    }
}
